Abstract
Introduction:
The anterior column of the spine is often destroyed by trauma or disease. It is reconstructed by using autograft, allograft, or synthetic cages. The fibula strut graft provides good strength, incorporates quickly and has less risk of disease transmission, which is a big advantage in communities with high incidence of HIV. Various authors cite that its major drawback is the size of its foot print. We could not find any literature that measures its size. We undertook a study to measure the size of the footprint of the fibular in relation to the surface area of the endplate. The clinical relevance is that it may guide the surgeon in deciding how many struts of fibular are required in reconstructing the anterior column, and also quantifies the statement that the fibular strut has a small footprint.
Material and Method:
CT angiograms are done frequently for peripheral vascular diseases. These angiograms also show CT scans of the lumbar and thoracic vertebrae, and fibulae of the same patient. We retrospectively examined the first 35 scans done during the year 2012 at Steve Biko Academic Hospital. From the CT we measured the surface area of the endplate of the vertebral bodies T6, 8, 12, L2, and the surface area of the cut surface of the proximal, middle and distal thirds of the fibular, all in square millimetres. We then compared the areas of the vertebral measurements to the area of the fibular measurements.
Results:
The middle third of the fibular had the biggest cross sectional surface area. This fact, together with anatomical features of the fibula, explains why the middle part of the fibular is the preferred graft donor site.
The ratio of the fibular surface area to that of the vertebral endplate is 1:3–6. It is difficult to advise in a biological system how many struts are required, as compared to a mechanical system. However these ratios suggest that more than one fibular strut graft is required to reconstruct the anterior column.
Conclusion:
This is the first time to our knowledge that the surface area of the fibular graft is quantified against the vertebral end plate surface area. The study shows that at least 2 fibula struts are required to reconstruct the thoracic and lumbar anterior columns.
